Check if the Internet is available

netisup.pl

#!/usr/bin/perl

use strict;
use warnings;
use Net::Ping;

my $host       = shift || 'www.google.com';
my $wait       = shift || 5;

my @states     = map { "Internet is $_ " } qw/down up/;
my $p          = Net::Ping->new("tcp", 2);
$p->{port_num} = getservbyname("http", "tcp");

my $is_up = 0;
while (1) {
    my $state = !!$p->ping($host);
    next if $state == $is_up;
    $is_up = $state;
    print "$states[$is_up]\n";
    #if on OS X, talk, otherwise beep
    if ($^O eq 'darwin') {
        system "say -v Victoria $states[$is_up]";
    } else {
        print "\a";
    }
} continue {
    sleep $wait;
}